The data on age were derived from answers to Question 2. The age classification is based on the age of the person in complete years at the time of interview. Both age and date of birth are used in combination to calculate the most accurate age at the time of the interview. Inconsistently reported and missing values are assigned or imputed based on the values of other variables for that person, from other people in the household, or from people in other households ("hot deck" imputation). Data on age are used to determine the applicability of other questions for a particular individual and to classify other characteristics in tabulations. Age data are needed to interpret most social and economic characteristics used to plan and analyze programs and policies. Therefore, age data are tabulated by many different age groupings, such as 5-year age groups.

The median age is the age that divides the population into two equal-size groups. Half of the population is older than the median age and half is younger. Median age is based on a standard distribution of the population by single years of age and is shown to the nearest tenth of a year. (See the sections on "Standard Distributions" and "Medians" under "Derived Measures.")

Caution should be taken when comparing population in age groups across time. The entire population continually ages into older age groups over time and babies fill in the youngest age group. Therefore, the population of a certain age is made up of a completely different group of people in 2000 and 2006. Since populations occasionally experience booms/increases and busts/decreases in births, deaths, or migration (for example, the postwar Baby Boom from 1946-1964), one should not necessarily expect that the population in an age group in Census 2000 should be similar in size or proportion to the population in the same age group in the 2006 ACS. For example, Baby Boomers were age 36 to 54 in Census 2000 while they were age 44 to 62 in the 2006 ACS. Therefore, the age group 55 to 59 would show a considerable increase in population when comparing Census 2000 data with the 2006 ACS data.
Beginning in 2006, the population in group quarters (GQ) is included in the ACS. Some types of GQ populations have age distributions that are very different from the household population. The inclusion of the GQ population could therefore have a noticeable impact on the age distribution. This is particularly true for areas with a substantial GQ population.

The 1996-2002 American Community Survey question asked for month, day, and year of birth before age. Since 2003, the American Community Survey question asked for age, followed by month, day, and year of birth. In 2006, an additional instruction was provided with the age and date of birth question on the American Community Survey questionnaire to report babies as age 0 when the child was less than 1 year old. The addition of this instruction occurred after 2005 National Census Test results indicated increased accuracy of age reporting for babies less than one year old.

Excerpt from:

Social Explorer; U.S. Census Bureau; American Community Survey 2006 Summary File: Technical Documentation.

For data products, a "civilian veteran" is a person 18 years old or over who has served (even for a short time), but is not now serving, on active duty in the U.S. Army, Navy, Air Force, Marine Corps, or the Coast Guard, or who served in the U.S. Merchant Marine during World War II. People who served in the National Guard or military Reserves are classified as veterans only if they were ever called or ordered to active duty, not counting the 4-6 months for initial training or yearly summer camps. All other civilians 18 years old and over are classified as nonveterans.

People who indicated that they had served on active duty or were now on active duty were asked to indicate the period or periods in which they served. The responses to the question about period of service were edited for consistency and reasonableness. The edit eliminated inconsistencies between reported period(s) of service and age of the person; it also removed reported combinations of periods containing unreasonable gaps (for example, it did not accept a response that indicated that the person had served in World War II and in the Vietnam era, but not in the Korean conflict).

For the 1996-1998 American Community Survey, people who indicated that they had served on active duty or were now on active duty were asked to report the total number of years and months of active-duty service.
Since 1999, people who indicated that they had served on active duty or were now on active duty were asked to report whether the total number of years of active-duty service was less than 2 years or 2 years or more. The question asked for accumulated service, which is not necessarily the same as continuous service.

There may be a tendency for the following kinds of persons to report erroneously that they served on active duty in the Armed Forces: (a) persons who served in the National Guard or Military Reserves but were never called to duty; (b) civilian employees or volunteers for the USO, Red Cross, or the Department of Defense (or its predecessors, the Department of War and the Department of the Navy); and (c) employees of the Merchant Marine or Public Health Service. There may also be a tendency for persons to erroneously round up months to the nearest year in Question 22. (For example, persons with one year and eight months of active duty military service may mistakenly report "2 years.")
Beginning in 2006, the population in group quarters (GQ) is included in the ACS. Some types of GQ populations may have period of military service and veteran status distributions that are different from the household population. The inclusion of the GQ population could therefore have a noticeable impact on the period of service and veteran status distributions. This is particularly true for areas with a substantial GQ population.

Veteran Status:For the 1999-2002 American Community Survey question, the response categories were modified by expanding the "No active duty service" answer category to distinguish persons whose only military service was for training in the Reserves or National Guard, from persons with no military experience whatsoever. Period of Military Service:For the 1999-2002 American Community Survey question, the response categories were modified by closing the "August 1990 or later (including Persian Gulf War)" period at March 1995, and adding the "April 1995" or later category. For the 2001-2002 American Community Survey question, the response category was changed from "Korean conflict" to "Korean War." Starting in 2003, the response categories for the question were modified in several ways. The first category "April 1995 or later" was changed to "September 2001 or later" to reflect the era that began after the events of September 11, 2001; the second category "August 1990 to March 1995" was then expanded to "August 1990 to August 2001 (including Persian Gulf War)." The category "February 1955 to July 1964" was split into two categories: "March 1961 to July 1964" and "February 1955 to February 1961." To match the revised dates for war-time periods of the Department of Veteran Affairs, the dates for the "World War II" category were changed from "September 1940 to July 1947" to "December 1941 to December 1946," and the dates for the "Korean War were changed from "June 1950 to January 1955" to "July 1950 to January 1955." To increase specificity, the "Some other time" category was split into two categories: "January 1947 to June 1950" and "November 1941 or earlier."

Excerpt from:

Social Explorer; U.S. Census Bureau; American Community Survey 2006 Summary File: Technical Documentation.

Poverty statistics in ACS products adhere to the standards specified by the Office of Management and Budget in Statistical Policy Directive 14. The Census Bureau uses a set of dollar value thresholds that vary by family size and composition to determine who is in poverty. Further, poverty thresholds for people living alone or with nonrelatives (unrelated individuals) vary by age (under 65 years or 65 years and older). The poverty thresholds for two-person families also vary by the age of the householder. If a familys total income is less than the dollar value of the appropriate threshold, then that family and every individual in it are considered to be in poverty. Similarly, if an unrelated individuals total income is less than the appropriate threshold, then that individual is considered to be in poverty.

In determining the poverty status of families and unrelated individuals, the Census Bureau uses thresholds (income cutoffs) arranged in a two-dimensional matrix. The matrix consists of family size (from one person to nine or more people) cross-classified by presence and number of family members under 18 years old (from no children present to eight or more children present). Unrelated individuals and two-person families are further differentiated by age of reference person (RP) (under 65 years old and 65 years old and over).
To determine a person's poverty status, one compares the person's total family income in the last 12 months with the poverty threshold appropriate for that person's family size and composition (see example below). If the total income of that person's family is less than the threshold appropriate for that family, then the person is considered "below the poverty level," together with every member of his or her family. If a person is not living with anyone related by birth, marriage, or adoption, then the person's own income is compared with his or her poverty threshold. The total number of people below the poverty level is the sum of people in families and the number of unrelated individuals with incomes in the last 12 months below the poverty threshold.
Since ACS is a continuous survey, people respond throughout the year. Because the income questions specify a period covering the last 12 months, the appropriate poverty thresholds are determined by multiplying the base-year poverty thresholds (1982) by the average of the monthly inflation factors for the 12 months preceding the data collection. See the table below titled "Poverty Thresholds in 1982, by Size of Family and Number of Related Children Under 18 Years (Dollars)," for appropriate base thresholds. See the table "The 2006 Poverty Factors" for the appropriate adjustment based on interview month.
For example, consider a family of three with one child under 18 years of age, interviewed in July 2006 and reporting a total family income of $14,000 for the last 12 months (July 2006 to June 2006). The base year (1982) threshold for such a family is $7,765, while the average of the 12 inflation factors is 2.19359. Multiplying $7,765 by 2.19359 determines the appropriate poverty threshold for this family type, which is $17,033. Comparing the familys income of $14,000 with the poverty threshold shows that the family and all people in the family are considered to have been in poverty. The only difference for determining poverty status for unrelated individuals is that the person's individual total income is compared with the threshold rather than the familys income.
For example, consider a family of three with one child under 18 years of age, interviewed in July 2006 and reporting a total family income of $14,000 for the last 12 months (July 2006 to June 2006). The base year (1982) threshold for such a family is $7,765, while the average of the 12 inflation factors is 2.19359. Multiplying $7,765 by 2.19359 determines the appropriate poverty threshold for this family type, which is $17,033. Comparing the familys income of $14,000 with the poverty threshold shows that the family and all people in the family are considered to have been in poverty. The only difference for determining poverty status for unrelated individuals is that the person's individual total income is compared with the threshold rather than the familys income.The 2006 Poverty Factors:

Interview Month

Poverty Factors

January

2.14841

February

2.15589

March

2.16297

April

2.17003

May

2.17705

June

2.18455

July

2.19359

August

2.20366

September

2.21330

October

2.22219

November

2.22879

December

2.23073

Poverty Thresholds in 1982, by Size of Family and Number of Related Children Under 18 Years Old (Dollars)

Poverty status was determined for all people except institutionalized people, people in military group quarters, people in college dormitories, and unrelated individuals under 15 years old. These groups were excluded from the numerator and denominator when calculating poverty rates.

For various reasons, the official poverty definition does not satisfy all the needs of data users. Therefore, some of the data reflect the number of people below different percentages of the poverty thresholds. These specified poverty levels are obtained by multiplying the official thresholds by the appropriate factor. Using the previous example cited (a family of three with one related child under 18 years responding in July 2006), the dollar value of 125 percent of the poverty threshold was $ 21,291 ($ 17,033x 1.25).

Income deficit represents the difference between the total income in the last 12 months of families and unrelated individuals below the poverty level and their respective poverty thresholds. In computing the income deficit, families reporting a net income loss are assigned zero dollars and for such cases the deficit is equal to the poverty threshold. This measure provides an estimate of the amount, which would be required to raise the incomes of all poor families and unrelated individuals to their respective poverty thresholds. The income deficit is thus a measure of the degree of the impoverishment of a family or unrelated individual. However, please use caution when comparing the average deficits of families with different characteristics. Apparent differences in average income deficits may, to some extent, be a function of differences in family size.

Aggregate income deficit refers only to those families or unrelated individuals who are classified as below the poverty level. It is defined as the group (e.g., type of family) sum total of differences between the appropriate threshold and total family income or total personal income. Aggregate income deficit is subject to rounding, which means that all cells in a matrix are rounded to the nearest hundred dollars. (For more information, see "Aggregate" under "Derived Measures.")

Mean income deficit represents the amount obtained by dividing the total income deficit for a group below the poverty level by the number of families (or unrelated individuals) in that group. (The aggregate used to calculate mean income deficit is rounded. For more information, see "Aggregate Income Deficit.") As mentioned above, please use caution when comparing mean income deficits of families with different characteristics, as apparent differences may, to some extent, be a function of differences in family size. Mean income deficit is rounded to the nearest whole dollar. (For more information on means, see "Derived Measures.")

When the original poverty definition was developed in 1964 by the Social Security Administration (SSA), it focused on family food consumption. The U.S. Department of Agriculture (USDA) used its data about the nutritional needs of children and adults to construct food plans for families. Within each food plan, dollar amounts varied according to the total number of people in the family and the family's composition, that is, the number of children within each family. The cheapest of these plans, the Economy Food Plan, was designed to address the dietary needs of families on an austere budget.
Since the USDAs 1955 Food Consumption Survey showed that families of three or more people across all income levels spent roughly one-third of their income on food, the SSA multiplied the cost of the Economy Food Plan by three to obtain dollar figures for total family income. These dollar figures, with some adjustments, later became the official poverty thresholds. Since the Economy Food Plan budgets varied by family size and composition, so too did the poverty thresholds. For two-person families, the thresholds were adjusted by slightly higher factors because those households had higher fixed costs. Thresholds for unrelated individuals were calculated as a fixed proportion of the corresponding thresholds for two-person families. The poverty thresholds are revised annually to allow for changes in the cost of living as reflected in the Consumer Price Index for All Urban Consumers (CPI-U). The poverty thresholds are the same for all parts of the country; they are not adjusted for regional, state, or local variations in the cost of living .

Because of differences in survey methodology (questionnaire design, method of data collection, sample size, etc.), the poverty rate estimates obtained from American Community Survey data may differ from those reported in the Current Population Survey, Annual Social and Economic Supplement, and those reported in Census 2000. Please refer to http://www.census.gov/hhes/www/poverty/newguidance.html for more details.

Since poverty is defined at the family level and not the household level, the poverty status of the household is determined by the poverty status of the householder. Households are classified as poor when the total income of the householder's family in the last 12 months is below the appropriate poverty threshold. (For nonfamily householders, their own income is compared with the appropriate threshold.) The income of people living in the household who are unrelated to the householder is not considered when determining the poverty status of a household, nor does their presence affect the family size in determining the appropriate threshold. The poverty thresholds vary depending upon three criteria: size of family, number of children, and, for one- and two- person families, age of the householder.

Beginning in 2006, the population in group quarters (GQ) is included in the ACS. The part of the group quarters population in the poverty universe (for example, people living in group homes or those living in agriculture workers dormitories) is many times more likely to be in poverty than people living in households. Direct comparisons of the data would likely result in erroneous conclusions about changes in the poverty status of all people in the poverty universe.

Excerpt from:

Social Explorer; U.S. Census Bureau; American Community Survey 2006 Summary File: Technical Documentation.

Using models of disability from the Institute of Medicine and the International Classification of Functioning, disability is defined as the restriction in participation that results from a lack of fit between the individual's functional limitations and the characteristics of the physical and social environment. So while the disability is not seen as intrinsic to the individual, the way to capture it in a survey is to measure components that make up the process. The American Community Survey identifies serious difficulty in four basic areas of functioning: vision, hearing, ambulation, and cognition. Described below, the ACS asks respondents about serious difficulty and the resulting data can be used individually or combined. The ACS also includes two questions to identify people with difficulties that might impact their ability to live independently. In the 2006 American Community Survey, there are three disability questions, two with subparts totaling six questions in all, as described below.

Beginning in 2006, the population in group quarters (GQ) is included in the ACS. The universe for most disability data tabulations is the civilian noninstitutionalized population. Some types of GQ populations have disability distributions that are different from the household population. The inclusion of the noninstitutionalized GQ population could therefore have a noticeable impact on the disability distribution. This is particularly true for areas with a substantial noninstitutionalized GQ population. For example, the number of people with a disability may increase in areas having a substantial group home population. In areas having a substantial college dormitory population, the percentage of people with a disability may decrease because the base of the percentage, which now includes the population in college dormitories, is larger.

The data on sensory and physical limitations were derived from answers to Questions 15a and 15b, which were asked of people 5 years old and over. Questions 15a and 15b asked respondents if they had any of the following two long-lasting conditions: "Blindness, deafness, severe vision or hearing impairment," or "A condition that substantially limits one or more basic physical activities such as walking, climbing stairs, reaching, lifting, or carrying." Respondents were instructed to mark "yes" or "no" for each long-lasting condition. Question 15a is labeled as "Sensory disability" and Question 15b as "Physical disability" for some of the disability data products such as the ACS Detailed Tables.

For the 1996-1998 American Community Survey, the question, which was asked of persons 5 years old and over, instructed the respondents to mark each appropriate box if they had difficulty with any of the following three specific functions: "Difficulty seeing (even with glasses)," "Difficulty hearing (even with a hearing aid)," or "Difficulty walking." The respondents could mark as many as three boxes depending on their functional limitation status. If the respondents did not have difficulty with any of the three specific functions, the question instructed them to mark the box labeled "None of the above." The sensory and physical disability data obtained from the 1996-1998 American Community Survey are not comparable to data collected from the 1999-2006 American Community Surveys.

The data on cognitive functioning were derived from answers to Question 16a, which was asked of people 5 years old and over. The question asked respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "learning, remembering, or concentrating." Respondents were instructed to mark "yes" or "no." Question 16a is labeled as "Mental Disability" for some disability data products such as the ACS Detailed Tables.

The data on self-care limitations were derived from answers to Question 16b, which was asked of people 5 years and over. The question asked respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "dressing, bathing, or getting around inside the home." Respondents were instructed to mark "yes" or "no." Question 16b is labeled as "Self-Care Disability" for some disability data products such as the ACS Detailed Tables.

The data on mobility limitations were derived from answers to Question 17a. Although Question 17a was asked of people 15 years and over, the data products only report this type of disability for people 16 years and over. The question asked respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "going outside the home alone to shop or visit a doctor's office." Respondents were instructed to mark "yes" or "no." Question 17a is labeled as "Go-outside-home Disability" for some disability products such as the ACS Detailed Tables.

The Census Bureau does not recommend trend analysis using the 2003-2006 data with years prior to 2003 due to the 2003 questionnaire change. For more information regarding the 2003 questionnaire change, view "Disability Data From the American Community Survey: A Brief Examination of the Effects of a Question Redesign in 2003" ( http://www.census.gov/hhes/www/disability/ACS_disability.pdf).

For the 1996-1998 American Community Survey, the data on going-outside-home limitations were derived from answers to Question 16a, which was asked of persons 16 years old and over. The question was slightly different from the 1999-2002 question and asked the respondents if they had a long-lasting physical or mental condition that made it difficult to "go outside the home alone to shop or visit a doctor's office." In the 1999-2002 American Community Survey, the going-outside-home question was part of Question 16. The 2003 questionnaire moved go-outside-home limitations to Question 17a and introduced a new skip instruction between Questions 16 and 17.

The data on employment limitations were derived from answers to Question 17b. Although it was asked of people 15 years and over, the data products only report this type of disability for people aged 16 to 64. The question asked the respondents if they had a physical, mental, or emotional condition lasting 6 months or more that made it difficult "working at a job or business." Respondents were instructed to mark "yes" or "no." Question 17b is labeled as "Employment Disability" for some disability data products such as the ACS Detailed Tables.

For the 1996-1998 American Community Survey, the data on employment limitations were derived from answers to Question 16b, which was asked of persons 16 years old and over. The question was slightly different from the 1999-2003 question and asked the respondents if they had a long-lasting physical or mental condition that "prevents this person from working at a job or business." In the 1999-2002 American Community Survey, the employment limitations question was part of Question 16. The 2003 questionnaire moved the employment limitations to Question 17b and introduced a new skip instruction between Questions 16 and 17.

The Census Bureau does not recommend trend analysis using the 2003-2006 data with years prior to 2003 due to the 2003 questionnaire change. For more information regarding the 2003 questionnaire change, view "Disability Data From the American Community Survey: A Brief Examination of the Effects of a Question Redesign in 2003" ( http://www.census.gov/hhes/www/disability/ACS_disability.pdf).

The Census Bureau uses the six disability questions above to determine an individual's disability status in some of its data products such as in the ACS Detailed Tables and the Disability Profile. People aged 16 to 64 were classified as having a disability if they reported at least one of the above six limitations. People aged 5 to 15 were classified as having a disability if they reported any one of the four limitations: sensory disability, physical disability, mental disability, or self-care disability. People 65 and over were classified as having a disability if they reported any one of the five limitations: sensory disability, physical disability, mental disability, self-care disability, or going-outside-home disability.

Since two of the six questions used to determine disability status are no longer comparable with those of the prior years, the Census Bureau does not recommend trend analysis using the 2003-2006 data with years prior to 2003. For more information regarding the 2003 questionnaire change, view "Disability Data from the American Community Survey: A Brief Examination of the Effects of a Question Redesign in 2003" ( http://www.census.gov/hhes/www/disability/ACS_disability.pdf).